class Player(object):
    numbers = 0
    def __init__(self, name, age, city):
        self.name = name
        self.age = age
        self.city = city
        Player.numbers += 1


    # @classmethod 表示类方法的装饰器
    @classmethod
    def get_players(cls):  # 类方法中是cls
        print('用户数量是%d人' %cls.numbers)


tom = Player('tom', 20, 'LA.')
Player.get_players()